基于另一个表中的id的MySQL更新表

Question

This is what I tried

update site
set value_id = 4464551
where (select id from base
where name = 'myName' and
discriminator = 'abc' and 
system_id = 001)

What I want is

• update the value_id in trget site where id = (inner select statement)

What I got
- it updated all the rows in site

Question
- how can I get one id that inner select statement returns?

Answer 1

The following query should work.

UPDATE site
SET value_id = 4464551
WHERE site.id = (
    SELECT id 
    FROM base
    WHERE name  'myName' AND 
        discriminator = 'abc' AND 
        system_id = 001
)

Or, if you're expecting multiple rows to be updated:

UPDATE site
SET value_id = 4464551
WHERE site.id IN (
    SELECT id 
    FROM base
    WHERE name  'myName' AND 
        discriminator = 'abc' AND 
        system_id = 001
)

Answer 2

You can also get what you want without using inner sql statements, for example:

update site, base
set site.value_id = 4464551
where 
base.name = 'myName' and
base.discriminator = 'abc' and 
base.system_id = 001 and
site.id = base.id